“悲观者”用英语怎么说？

有些人是悲观者: 他们总认为事情是多糟或是将会是多糟.Some people are pessimists: they always think about how bad things are or will be.投资者多元化则意味着市场既需要乐观者也需要悲观者.Investor diversity and heterogeneity is predicated on the notion that market needs bot...